How building London's below ground infrastructure has improved the geological knowledge of the capital. A talk by John Davis

In Person/Hybrid

02 March 2027

Abstract: Most of the existing knowledge of London's geology has come from relatively shallow
(<10m deep) boreholes or poorly logged deep water wells. There are no outcrops. Most pre-war
and many post war buildings are low rise and employ shallow foundations that sit above the water
table. These are low risk structures from a design and construction perspective.
Until the 1970s most 'tube' (circular) tunnels stuck to the relatively low risk and benign London
Clay. Tunnelling technology at that time meant larger surface settlements were inevitable.
Since then, newer tube alignments have been forced deeper and have gone farther east into much
more challenging ground beyond and below the London Clay. Technological change has made this
possible.
This presentation sets out some of the geological lessons learned from this work with a focus on
faulting. An outline of modern soft ground tunneling techniques will be provided.